Texas Instruments MSP430x1xx - Manual (Page 323)

ADC12 Control Registers
15-33
ADC12
SHT0 bits
8–11 Sample-and-hold Time0. These bits define the sample timing for
conversions whose results are stored in conversion-memory registers
ADC12MEM0 to ADC12MEM7.
The sample time is a multiple of the ADC12CLK
×
4:
t
sample
= 4
×
ADC12CLK
×
n
SHT0 0 1 2 3 4 5 6 7 8 9 10 11 12–15
n 1 2 4 8 16 24 32 48 64 96 128 192 256
SHT1 bits
12–15 Sample-and-hold Time1. These bits define the sample timing for
conversions whose results are stored in conversion-memory registers
ADC12MEM8 to ADC12MEM15.
The sample time is a multiple of the ADC12CLK
×
4:
t
sample
= 4
×
ADC12CLK
×
n
SHT1 0 1 2 3 4 5 6 7 8 9 10 11 12–15
n 1 2 4 8 16 24 32 48 64 96 128 192 256
rw –(0) rw –(0) rw –(0) rw –(0)
01A2h
ADC12CTL1
rw –(0) rw –(0) rw –(0) r –(0) rw –(0) rw –(0) rw –(0) rw –(0)
7 0 15 8
ADC12SSEL ADC12DIV CSStartAdd
rw –(0) rw –(0) rw –(0) rw –(0)
CONSEQ SHS
ADC12
BUSY ISSH SHP
ADC12BUSY bit0 The ADC12BUSY bit indicates an active sample or conversion operation. It
is used specifically when the conversion mode is single-channel-
single-conversion, because if the ENC bit is reset in this mode, the
conversion stops immediately and the results are invalid. Therefore, the
ADC12BUSY bit should be tested to verify that it is 0 before resetting the
ENC bit when in single-channel-single-conversion mode.
The busy bit is not useful in all other operating modes because resetting the
ENC bit does not immediately affect any other mode.
0: No operation is active.
1: A sample period, conversion or conversion sequence is active.
CONSEQ bits
1–2 The CONSEQ bits select the conversion mode. Repeat mode is on if the
CONSEQ.1 is set.
0: Single-channel-single-conversion mode. One single channel is
converted once.
1: Sequence-of-channels mode. A sequence of conversions is executed
once.
2: Repeat-single-channel mode. Conversions on a single channel are
repeated until CONSEQ is set to 0 or 1.
3: Repeat-sequence-of-channels. A sequence of conversions is repeated
until CONSEQ is set to 0 or 1.
NOTE: See also section Conversion Modes.